US4885146A - Process for scrubbing of NO and/or SO2 from gas mixtures - Google Patents

Process for scrubbing of NO and/or SO2 from gas mixtures Download PDF

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US4885146A
US4885146A US07/174,474 US17447488A US4885146A US 4885146 A US4885146 A US 4885146A US 17447488 A US17447488 A US 17447488A US 4885146 A US4885146 A US 4885146A
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scrubbing agent
process according
scrubbing
ions
agent
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Eberhard Lassmann
Robert Helmling
Franz Beran
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Linde GmbH
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Linde GmbH
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/507—Sulfur oxides by treating the gases with other liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/60—Simultaneously removing sulfur oxides and nitrogen oxides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Definitions

  • This invention relates to a process and an apparatus for scrubbing of NO x and/or SO 2 from gas mixtures containing NO x and/or SO 2 with a scrubbing agent containing an iron(II) salt and solvent.
  • Air pollution especially egregious during episodes of smog, has its origin mainly from the exhaust gases from fossil fuel power plants, other large-scale industrial facilities (e.g., iron and steel plants, petroleum refineries) and automobile exhaust gases.
  • the main components of the air pollution are CO, SO 2 , hydrocarbons, NO x and suspended particles.
  • SO 2 together with suspended particles is often considered as an indicator for the entire air pollution, and to appreciate the scope of the problem, it is noted that SO 2 emission by burning of sulfur-containing fossil fuels in the Federal Republic of Germany is estimated at several million tons yearly.
  • SO 2 is easily soluble in water and above all acts as an irritant to the mucous membranes of the upper and middle respiratory tract and of the eyes.
  • NO x is formed from the elements in combustion processes.
  • NO in the air is generally quickly oxidized to NO 2 , which because of its high water solubility is resorbed in the lung alveoli and causes an irritating effect.
  • any residual NO is considered to be an extraordinarily harmful air pollutant, because under the effect of ultraviolet radiation it can react with hydrocarbons, CO and water vapor, as they occur in automobile exhaust gases, to form photochemical oxidation products, especially ozone.
  • Particularly harmful photochemical reaction products are organic peroxides and nitric acid compounds of peracetic acid, which have a considerable toxicity for the respiratory tract and which damage goods and vegetation.
  • Kulik refers to the use of a "nonaqueous scrubbing solution".
  • nonaqueous is meant an aqueous solution to which nonaqueous liquids have been added, e.g., alcohols.
  • the alcohol in the scrubbing solution provides an "anhydrous environment" which improves the stability of the NO complex and that other "nonaqueous liquids" can be used "in combination with a ferrous thiosulfate scrubbing solution.”
  • a scrubbing solution comprising a total of 240 mol containing 40 mol of methanol was used.
  • this known process employs a molar ratio of S 2 O 3 -- /Fe ++ of about 5.0.
  • this known process has the disadvantage of a very high consumption of chemicals.
  • a molar ratio of S 2 O 3 -- /Fe ++ of about 5.0.
  • this known process has the disadvantage of a very high consumption of chemicals.
  • 190 g of K 2 S 2 O 3 and 49 g of H 2 SO 4 are consumed.
  • the known scrubbing agent apparently cannot be regenerated easily, if at all.
  • Another object of this invention is to provide a process for removal of NO x and/or SO 2 from gas mixtures by scrubbing wherein the scrubbing agent is reuseable.
  • the operation is performed with a scrubbing agent which to a substantial extent consists of a nonaqueous solvent.
  • the process according to the invention is performed with a water-free nonaqueous solvent.
  • the scrubbing agent according to the invention develops its greatest solvent power for NO and/or SO 2 .
  • flue gases for example, are usually moist, so that the scrubbing agent absorbs certain amounts of water during the operation.
  • Suitable organic compounds for use as the nonaqueous solvent of the scrubbing agent include those of formula I
  • R 1 when R 1 is an O alkyl group, the alkyl portion preferably contains 1 to 10, in particular 1 to 3, C atoms.
  • R 1 can be methyl or ethyl.
  • R 1 is a keto group
  • the group is preferably in the form of COR 6 wherein R 6 is an alkyl group of 1 to 10, preferably 1 to 4, C atoms.
  • R 6 can be methyl or ethyl.
  • R 1 is an ester group
  • the ester group is preferably in the form of COOR 7 wherein R 7 is an alkyl group of 1 to 10, preferably 1 to 3, C atoms.
  • R 7 can be ethyl.
  • R 1 is an ester group
  • the ester group is also preferably an ester of an inorganic acid such as, for example, a mono-, di-, or triester of phosphoric acid or of phosphonic acid.
  • R 2 is ##STR3##
  • the carbon atom can be preferably unsubstituted or substituted with alkyl groups of 1 to 5, in particular 1 to 2, C atoms.
  • R 2 can be methyl or ethyl.
  • R 3 when R 3 is an O alkyl group, the alkyl portion preferably contains 1 to 10, in particular 1 to 3, C atoms.
  • the alkyl can be methyl or ethyl.
  • the keto group can preferably be of the formula COR 8 wherein R 8 is an alkyl group of 1 to 10, in particular 1 to 4, C atoms.
  • R 8 can be methyl or ethyl.
  • the alkyl preferably is a cyclic alkyl group with 5 to 6 C atoms.
  • the alkyl can be cyclohexyl.
  • the cyclic structure may also contain other atoms, such as O, N, S or P.
  • R 3 is an (O--CH 2 --CH 2 ) n --O alkyl group
  • the alkyl portion preferably contains 1 to 10, in particular 1 to 4, C atoms and n is preferably 1 to 10.
  • R 3 can be (O--CH 2 --CH 2 ) 4 --O--C 2 H 5 .
  • R 3 is an (O--CH 2 --CH 2 --CH 2 ) n --O alkyl group
  • the alkyl portion preferably contains 1 to 10, in particular 1 to 4, C atoms and n is preferably 1 to 10.
  • R 3 can be (O--CH 2 --CH 2 --CH 2 ) 3 --O--CH 3 .
  • R 4 when R 4 is an O alkyl group, the alkyl portion preferably contains 1 to 10, in particular 1 to 4, C atoms.
  • the alkyl can be methyl or ethyl.
  • R 4 is a keto group
  • the group is preferably in the form of COR 9 wherein R 9 is an alkyl group of 1 to 10, preferably 1 to 4, C atoms.
  • R 9 can be methyl or ethyl.
  • R 4 is an ester group
  • the ester group is COOR 10 wherein R 10 is an alkyl group of 1 to 10, preferably 1 to 3, C atoms.
  • R 10 can be ethyl.
  • R 4 is an ester group
  • another preferred group is of an inorganic acid such as, for example, a mono-, di-, or triester of phosphoric acid or of phosphonic acid.
  • the alkyl portio preferably contains 1 to 10, in particular 1 to 3, C atoms.
  • the alkyl can be methyl or ethyl.
  • the keto group can preferably be of the formula COR 11 wherein R 11 is an alkyl group of 1 to 10, in particular 1 to 4, C atoms.
  • R 11 can be methyl or ethyl.
  • R 5 is an (O--CH 2 --CH 2 ) n --O alkyl group
  • the alkyl portion preferably contains 1 to 10, in particular 1 to 4, C atoms and n is preferably 1 to 10.
  • R 5 can be (O--CH 2 --CH 2 ) 5 --O--CH 3 .
  • R 5 is an (O--CH 2 --CH 2 --CH 2 ) n --O alkyl group
  • the alkyl portion preferably contains 1 to 10, in particular 1 to 4, C atoms and n is preferably 1 to 10.
  • R 5 can be (O--CH 2 --CH 2 --CH 2 ) 3 --O--C 2 H 5 .
  • mono and diethers of oligoethylene and propylene glycols are suitable as nonaqueous solvents for the purposes of the process according to the invention.
  • dimethyl sulfoxide is a highly suitable solvent according to the invention.
  • phosphoric esters are also very suitable as solvents, since, besides having a very good solvent power for NO, they have the advantage of very low viscosity at very high boiling points. Namely, mono-, di- and triesters are suitable, whereby the mono- and diesters can be substituted on the phosphorus atom. As an example for these phosphonium compounds triethylphosphonoacetate may be mentioned.
  • the alcohol component of the scrubbing solution is used to provide an anhydrous environment which improves the stability of the NO complex formed during absorption.
  • Kulik discloses that other non-aqueous liquids can be substituted in place of the alcohol.
  • any non-aqueous liquid which is substituted for the alcohol must not deleteriously affect the overall solvent ability of the scrubbing agent with regard to dissolution of the sources of Fe +2 and S 2 O 3 -2 ions.
  • the solubility of (NH 4 ) 2 S 2 O 3 in grams per liter is provided for several scrubbing agents containing 20% by weight water and the remainder a nonaqueous liquid.
  • solubilities are low except for the cases where ethylene glycol is employed as the non-aqueous component.
  • Kulik disclose at Col. 2, Lines 33-38, that, for an S 2 O 3 -2 /FeSO 4 mole ratio of 5, NO absorption is 92% for an S 2 O 3 -2 ion concentration of 3.32 mole/liter (372 g/1) and 70% for an S 2 O 3 -2 ion concentration of 1.3 mole/liter (145.6 g/1).
  • Phase separation means that the mixture is separated into an aqueous rich phase and an organic phase with the aqueous phase containing the bulk of the salt while the organic phase exhibits the known low solubility for the salt.
  • solubilities provided in the above table are also relevant to the solubility of K 2 S 2 O 3 in the listed scrubbing agents, since the solubility behavior of K + ions and NH 4 + ions is similar.
  • the above-listed scrubbing agents if HC1or another acid is added thereto, the thiosulfate ion becomes unstable and decomposes resulting in the precipitation of sulfur.
  • solvents suitable for use in the scrubbing agent are selected preferably with respect to the following parameters:
  • the scrubbing agents according to the invention exhibit a minimum solubility of NO of about 500 ml/liter of solvent (STP) at an NO partial pressure of 0.85 mbar (temperature equals 25° C.).
  • the scrubbing agents exhibit a minimum solubility of SO 2 of about 200 ml/liter of solvent (STP) at a SO 2 partial pressure of 0.1 mbar.
  • the scrubbing agents according to the invention exhibit a maximum solubility of 2,000 ml/liter of solvent (STP) at a CO 2 partial pressure of 0.1 bar.
  • the process according to the invention does not require the presence of thiosulfate (S 2 O 3 -- ) ions.
  • S 2 O 3 -- thiosulfate
  • thiosulfate ions are preferably not added to the scrubbing agent. Under acidic conditions, the thiosulfate ions would not be stable in the scrubbing agents. The ions decompose resulting in the formation of elemental sulfur. For this reason, the thiosulfate ion content of the scrubbing agents according to the invention is preferably below about 1 g/1 .
  • a further important feature according to the process of the invention is that the divalent iron used in the scrubbing agent be in the form of its halides, especially in the form of the chloride. It does not seem to be critical whether FeC1 2 is added directly to the scrubbing agent or whether chloride ions in the form of another chlorine compound, e.g., HC1, are added to a solution of Fe(II) ions.
  • the addition of hydrochloric acid is advantageous because, as was also established according to the invention, a small amount of acid in the scrubbing agent, about 0.1 to 1% by weight, has a favorable effect on the absorption process and stability of the Fe ++ .
  • the scrubbing agent has a pH of about 1 to 2.
  • an oxidation inhibitor e.g., 4,4'-butylidenebis(6-tert-butyl-m-cresol).
  • 4,4'-butylidenebis(6-tert-butyl-m-cresol) is added to the scrubbing agent.
  • a preference as to the ratio of Fe +2 ions to NO present in the gas being treated e.g., moles/1 to mbar
  • the scrubbing agent acts as a chemical solvent with the formation of a complex between Fe +2 ions and NO.
  • the ratio of Fe +2 to NO is 0.08-0.5 mole/1 NO, preferably 0.1-0.2 mole/1 NO.
  • the structure of the NO-complex has not been determined, although it is known that the complex exhibits a very strong green or blue color. At saturation, the proportion of NO to Fe +2 amounts to about 1:1.
  • gases having an NO content of preferably about 80-2,000 vppm can effectively be treated for removal of NO x .
  • the scrubbing agent employed in the process contains a sufficient amount of Fe +2 ions to bind substantially all of the NO x contained in the gas to be treated.
  • the treated gases possess an NO x concentration of about 1-80, preferably 10-50 vppm NO.
  • the process according to the invention it is possible to remove both NO/NO x alone and NO/NO x together with SO 2 from industrial gas mixtures such as, e.g., flue gas.
  • the NO 2 if present in the gas is scrubbed out with the NO on the basis of natural physical laws.
  • the scrubbing agent can be regenerated by steam in a conventional manner.
  • the condensate from the regeneration steam has an extremely slight solubility for NO, so that in the regeneration, if the scrubbing agent is loaded only with NO/NO x , a highly concentrated NO-rich gas can be obtained, which by oxidation with air (without catalyst), can very easily be converted to NO 2 and then to concentrated nitric acid.
  • SO 2 is to be removed at the same time with the NO, this can be accomplished in the same step of removal of the NO, without resorting to other process steps or chemicals, because the solvents proposed according to the invention have a very good solubility in regard to SO 2 .
  • the SO 2 does not go into any reaction with the iron(II) ions but is dissolved purely physically by the nonaqueous solvent. Both dissolved components can then, like the NO alone, be stripped with steam from the scrubbing agent.
  • the first procedure includes condensing out the SO 2 which, because of the great difference in boiling points in relation to NO, is easily possible.
  • the NO-rich flue gas, substantially free of SO 2 is then oxidized by addition of air or oxygen, whereby in a known way (without pressure, without catalyst, and at about 20 to 30° C.) NO 2 is formed.
  • the NO 2 is then dissolved in water to form nitric acid.
  • the residual gases can be recycled back to a point upstream of the scrubbing step.
  • the second procedure involves directly oxidizing SO 2 -NO-rich gas with air or oxygen and bringing it in contact with water whereby a mixture of sulfuric and nitric acid is produced.
  • the reactions take place in a way similar to that in the case of the known lead-chamber process, as disclosed in Ullmanns Encyklopaedia der ischen Chemie, 3. Auflage, Band 15, pages 432-433.
  • This acid mixture can be used directly for fertilizer production, for example, by neutralization with Mg, Ca or K carbonates or hydroxides or with NH 3 .
  • the mixture can be separated into sulfuric acid and nitric acid according to known processes, e.g., by distillation.
  • the residual gases can either be recycled back to a point upstream of the scrubbing step or they can be worked up in separate steps.
  • the installation of two separate scrubbing circuits is necessary.
  • the first then serves for removal of the SO 2 , the second for removal of the NO.
  • This has the advantage that the same solvent travels in both scrubbing circuits so that overflow from one into the other circuit does not cause trouble.
  • any other suitable scrubbing agent e.g., a known milk of lime scrubbing solution
  • the invention therefore makes it possible to equip existing flue gas purification installations, which are already equipped with an SO 2 scrubbing but are unsatisfactorily or not at all equipped for removal of NO, with a subsequent or fine purification stage which assures a practically complete NO removal.
  • Fe(II) ions used in the NO absorption process are more or less quickly oxidized to inactive Fe(III) ions. It has been surprisingly shown that an addition of Fe(III) salts very considerably reduces the oxidation rate. Thus, it has proved advantageous to add to the scrubbing agent according to the invention Fe(III) ions in an amount which corresponds to 1- to 6-fold, preferably 2- to 3-fold the amount of dissolved Fe(II) ions.
  • Process A has the advantage that in the reaction no products are formed which could disturb the scrubbing process or the further processing of the gases. Moreover, the reaction takes place, in relation to the hydroxyl, with 60 to 95% yield and in a very short time (10 to 60 sec).
  • Process B is linked to the presence of electric current. Still, it is available cheaply as a rule, especially, of course, in flue gas purification at power plants.
  • cathode materials practically all marketable materials are suitable, preferably iron or nickel.
  • anode materials all marketable materials, preferably carbon or graphite, are suitable.
  • the form and arrangement of the electrodes and diaphragm play a role in the economic efficiency of the electrolytic reduction but not for their ability to function. Care must merely be taken to ensure that the scrubbing liquor passes through the reaction spaces as uniformly as possible.
  • the temperature of the electrolysis cell can be in the range of 0 to 100° C. However, the most favorable current efficiencies are reached in the range of 10 to 30° C.
  • process C according to the invention has proven most advantageous for the reduction of excessive Fe(III) ions.
  • the scrubbing medium as a rule is slightly acidic, either because of the acidic components contained in the flue gas or because of addition of an acid, the reaction between elementary iron and the Fe(III) ions to form Fe(II) ions takes place smoothly.
  • the elementary iron can be fed upstream of the head of the scrubbing column in the form of powder, cuttings, sheet pieces, etc.
  • This kind of reduction according to the invention of excess Fe(III) ions has the outstanding advantage that in the reaction no types of products result other than those that in any case are present in the scrubbing agent.
  • a concentration of Fe(III) ions occurs, which in extended operating periods make measures for their removal necessary.
  • process variant C1 a diverted partial stream of the scrubbing agent loaded with salts to be removed is completely subjected to vacuum distillation.
  • Process variant C1 is preferably performed after regeneration, i.e., after removal of NO x /SO 2 components from the scrubbing agent, but before cooling of the scrubbing agent, so that the latter is introduced into variant C1 at approximately 80 to 100° C.
  • the organic solvent can in this case be distilled off from the remaining constituents without any problem.
  • the hydrochloric acid dissolved in the scrubbing agent goes into the distillate and thus can immediately be reused in the scrubbing, which contributes to the reduction of operating costs.
  • the remaining bottoms remain pumpable and can be disposed of in a dump site.
  • the invention in this case it is favorable to use a 50% NaOH solution so as to introduce as little water as possible into the scrubbing agent. It has been shown that concentrated NaOH solution is practically insoluble in the solvents according to the invention. Since NaC1 is surprisingly slightly soluble in the solvents according to the invention, the neutralization products of the above reaction are all precipitated and can easily be separated from the solvent by settling or filtration.
  • the absorption rate for the components to be removed is an essential quantity for the economic efficiency of a gas scrubbing operation.
  • the solvent according to the invention is far superior to known solvents.
  • Scrubbing column 2 includes a lower, middle and upper section. In the lower section, the flue gas is scrubbed with water to remove dust, soot, HC1 and HF.
  • the working up of the water carrying the dirt load is diagrammatically represented by block 3.
  • another water scrubbing circuit is installed, whose working up is diagrammatically represented by block 4, which has the object of removing the entrained droplets of scrubbing agent from the middle section of scrubbing column 2, to keep the losses of scrubbing agent low.
  • the flue gas goes from the lower section into the middle section of scrubbing column 2, where it is sprayed with 800 m 3 /h of scrubbing agent (components, see example VI), delivered by pipe 5.
  • the scrubbing agent thus absorbs the NO and SO 2 contained in the flue gas.
  • powered iron can be introduced into the scrubbing column from time to time by pipe 6.
  • the scrubbed flue gas then goes into the upper section of scrubbing column 2, is freed of the entrained scrubbing agent and leaves the installation by pipe 7.
  • Loaded scrubbing agent is drawn off with a pump 8 by pipe 9, heated in heat exchanger 10 and fed into the upper part of a regenerating column 11, which is equipped with bottom heating and head cooling.
  • a regenerating column 11 the loaded scrubbing agent is freed, by heating, of the gas components NO and SO 2 dissolved therein, which leave the column as rich gas by pipe 12.
  • the rich gas is cooled in air condenser 13 and the water thus condensing is separated from the gas in separator 14 and removed by pipe 15. This is 5 t/h at most.
  • About 700 m 3 /h of rich gas then arrives by pipe 16 into condenser 17, in which the temperature is below the condensation temperature of the SO 2 .
  • the condensing SO 2 (860 kg/h) is separated from the gas in separator 18 and worked up to sulfuric acid in an installation represented as block 19.
  • the installation delivers about 1310 kg/h of H 2 SO 2 by pipe 20.
  • the NO-rich gas escaping from separator 18 by pipe 21 is mixed with air introduced by pipe 22 and fed to a trickling tower 23, in which it is sprayed with water (pipe 24) and thus, by intermediate formation of nitrous acid, is converted into 40 to 50% nitric acid.
  • a trickling tower 23 in which it is sprayed with water (pipe 24) and thus, by intermediate formation of nitrous acid, is converted into 40 to 50% nitric acid.
  • 440 kg/h of HNO 3 can be removed from the installation by pipe 25. Unreacted gas as a rule is recycled via pipe 26 to the flue gas that is to be treated.
  • the regenerated scrubbing agent flows from the bottom of regenerating column 11 by pipe 27.
  • a part of the scrubbing agent is pumped via pipe 5 through heat exchanger 10 and water condenser 28 by a pump 29 to the middle section of scrubbing column 2, while the rest, namely 340 1/h is transferred to an agitated vessel 30.
  • a suitable amount of 50% aqueous NaOH solution is fed to agitated vessel 30 by pipe 31 to precipitate the Fe(III) ions contained in the scrubbing agent as Fe(OH) 3 .
  • the reaction mixture then is delivered to a decanter 32.
  • Scrubbing agent with a reduced content of Fe(III) ions is removed from decanter 32 by pipe 33 and delivered to pipe 5, while Fe(OH) 3 slurry is removed by pipe 34 and delivered to a second agitated vessel 35 where it is diluted with water (pipe 36).
  • the mixture in vessel 35 is then delivered to a second decanter 37.
  • the supernatant scrubbing agent is fed by pipe 38 to a stripping column 39, where the scrubbing agent is supplied, by heating with a steam coil 40, with heat which causes evaporation, which is drawn off from the head of column 39 and liquefied in a water condenser 41.
  • the bottom liquid flows into a decanter 42, where NaC1 settles.
  • the NaC1 is transferred by pipe 43 to a dump site, while desalted scrubbing agent is delivered to pipe 5 by pipe 33.
  • Slurry from decanter 37 is transferred by pipe 44 into a third agitated vessel 45 and mixed once again with water (pipe 46).
  • a separation into scrubbing agent and slurry occurs in a decanter 47.
  • the scrubbing agent is transferred to pipe 38 by pipe 48, while the slurry is carried by pipe 49 to a dump site.
  • the regeneration took place in a regenerating column of the same structure as the scrubbing column at about 80° C. with 230 1/h of N 2 as regeneration gas
  • the regeneration took place in a regenerating column of the same structure as the scrubbing column at about 80° C. with 100 1/h of N 2 as regeneration gas.
  • the regeneration took place in a regenerating column at about 80° C. with 230 1/h of N 2 as regeneration gas.
  • Slurry from decanter 37 is transferred by pipe 4 into a third agitated vessel 45 and there once more is mixed with water (pipe 46).
  • a separation into scrubbing agent and slurry occurs in a decanter 47.
  • the scrubbing agent arrives at pipe 38 through pipe 48, while the slurry is carried by pipe 49 to a dump site

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US07/174,474 1985-09-27 1988-03-28 Process for scrubbing of NO and/or SO2 from gas mixtures Expired - Fee Related US4885146A (en)

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DE3534526 1985-09-27
DE3534526 1985-09-27
DE19863612123 DE3612123A1 (de) 1985-09-27 1986-04-10 Verfahren zum auswaschen von no und/oder so(pfeil abwaerts)2(pfeil abwaerts) aus gasgemischen
DE3612123 1986-04-10

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US5785888A (en) * 1995-03-24 1998-07-28 Milmac Operating Company Method for removal of sulfur dioxide
US5851265A (en) * 1996-09-03 1998-12-22 Monsanto Company Selective removal and recovery of sulfur dioxide from effluent gases using organic phosphorous solvents
US6652821B1 (en) * 1999-02-18 2003-11-25 Yasuo Fukutani Purificating agent for flue gas and incinerated ash and purificating method using the same
US6881243B1 (en) 1999-10-12 2005-04-19 Lextran Ltd. Method for removing acidic gases from waste gas
US20050214193A1 (en) * 2004-03-25 2005-09-29 D Ottone Luca Nitric oxide purification method and apparatus
EP2409752A4 (fr) * 2009-02-16 2012-08-15 Beijing Boyuan Hengsheng High Technology Co Ltd Procede d'elimination de sox contenus dans du gaz au moyen de polyethylene glycol
EP3045219A4 (fr) * 2013-09-10 2017-05-17 Beijing Boyuan-Hengsheng High-Technology Co., Ltd. Procédé d'élimination des sox contenus dans un gaz au moyen de polyéthylène glycol modifié
CN110448994A (zh) * 2019-08-16 2019-11-15 北京化工大学 一种可再生胺基功能化低共熔溶剂捕集no的工艺方法

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EP0216388A2 (fr) 1987-04-01
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